If audited, the IRS does not have to award any deduction that you can't prove.
I have heard various stories on this. Such as a customer who complained the IRS denied all their Goodwill donations because they had the standard, Goodwill form letter for each. I don't know how common this is or whether different auditors have different standards.
For myself, I do the following: I make a written, dated inventory of items and approximate values, and staple it to the form letter. For large donations, I take pictures and save them on my hard drive with other tax documents. In all cases you should have a contemporaneous written record of your items, with enough detail to allow you to determine value. (This will vary from item to item of course.)
Even then, I have read at least one customer complaint here that the examiner denied the donation because there was no proof that the items on the list were actually donated. So you could potentially take the extra step of preparing your inventory ahead of time, and asking someone at Goodwill to sign it when you drop off the donation. Don't use unattended drop boxes, only go to the Goodwill store when someone is there, or donate to a different charity where someone will sign your inventory (VOA, DVA, etc.) Whether you also get a form letter or get someone to sign your inventory is worth thinking about, if you can't get a full acknowledgment.
As-is for 2019, you've got what you've got. I wouldn't not claim legitimate deductions just out of fear of the IRS. But that's the best I can tell you.
And yes, Turbotax will generate a form 8283 for you. And you don't send your receipts to the IRS, just keep them for at least 3 years in case of audit.
